Design of an adjustable polarization-independent and wideband electromagnetic absorber

Abstract

An adjustable polarization-independent electromagnetic absorber based on a frequency-selective surface is proposed for both C and X microwave-band applications. The design using a symmetric fan-shaped pattern significantly reduces the sensitivity to different polarizations of normal incident microwaves. To achieve adjustability, PIN diodes are connected between patterned unit cells. By incorporating inductors into the metal patterns, an S-shaped series bias provides the bias voltage to PIN diodes. By tuning the working states of the diodes, an adjustable absorption performance from 4.6 to 13 GHz is achieved for both transverse electric and transverse magnetic polarizations in normal incidence.